johnson



(Model.)

E. E. JOHNSON.

TELEPHONE.

Patented Jan. 25,1887.,

AT TEST:

INVENT 0B:

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EDW'ARD H. JOHNSON, OF NEV YORK, N. Y.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 356,688, dated January 25, 1887.

Application iiled November l5, 1883. Serial No. 111,817. (lli'odel` To aZZ whom it may concern..-

Be it known that I, "EDWARD II. Jonsson, of New York city, in the county and State of Kew York, have invented a certain new and useful Improvement in Telephones, of which the following is a specification.

y The object I have in View is to produce a telephone hy which articulate speech can be transmitted practically and successfully by means of electrodes of platinum or other metals.y

In carrying out my invention I make use of a diaphragm composed of felt or an equivalent material, which controls the movement of one 3 of the electrodes, and, having but little capability of ribratiomprevents such electrode from ever moving` so far as to so separate the eleotrodes that they cannot quickly return to their normal position of contact, so that all the soundvibrations are responded to from the normal positionr of the electrodes.

Lfi

My invention consists, principally, in the use of such a diaphragm for the sound-receiving devine of a telephone-transmitter. One contact of the telephone is carried by the peculiar diaphragm, While the other I have found it hest to mount upon a yielding surface of the same nature as the diaphragm. This baci; Contact or electrode is made ado justable by means of a screw or otherwise, and by reason of its peculiar nature the limits of adjustment of the instrument are greatly increased. The hack contact is preferably a piece of platinum foil carried by the yielding surface; but it may be a hard point of platinum secured to the foil `or placed directly on the yielding support. To prevent had effects from the air-rushes produced in talking, I employ a second or auxiliary diaphragm, like the first or main diaphragm, but separated from it by an air-space. These specific features also form part of the invention.

In the accompanying drawings, forming a part hereof, Figure l is a seetional View of a telephone embodying my invention; Fig. 2, an elevation from the rear of the same, and Fig. 3 an enlarged sectional View of the contants or electrodes of the telephone and the parts carrying them.

Like letters denote corresponding parts in all three gures.

A is a diaphragm of felt or equivalent material-such as a number of thicknesses of some textile fabric secured together. This diaphragm is clamped at its periphery in a suitable oase or shell, B. It carries a contactpoint or electrode, a, secured to its center, and thisbears upon a back contact, b, which is a disk of yielding platinum foil clamped against a small diaphragm, c, of felt or equivalent material, secured in a cup, C. This cup is carried by the end of a screw, D, passing through a bridgepiece, E, and by adj listing the screw the adjustment of the instrument is aecomplished. I

The bridge-piece E carries two bindingposts, d e, the post d being insulated, and the circuit-connections 1 2 run to these posts.

A. line-Wire connection, 3, is made from the Contact a on the diaphragm A to the insu lated binding-post d.

An auxiliary diaphragm, Il, is preferably employed. This is also of felt or equivalent material, and is separated from the diaphragm A hy an air-space formed by the separatingring f. This auxiliary diaphragm, as before stated, is used to prevent had effect from the air-rushes produced in speaking into the instrument.

I am aware that it has been proposed to use a felt diaphragm in an acoustic telephone; but such a telephone having no electrodes, the peculiar advantages hereinhefore stated arising from the combination of such a diaphragm with 'electrodes is not attained.

"What I claim is 1. In an electric-telephone transmitter, a sound -reoeiving device or diaphragm oomposed of felt or equivalent material, in combination with an electrode or contact-point controlled thereby, substantially as set forth.

2. In a telephonetransmitter, the combination, with a diaphragm or soundueceiver and an electrode carried thereby, of another electrede separately supported upon a backing of felt or equivalent material, substantially as set forth.

3. In a telephone-transmitter, the combination, with the diaphragm of felt or equivalent material andthe front electrode Carried thereby, of the haelt. electrode supported by felt or equivalent material, substantially as set forth.

ICO

4.. In a telephone, the combination, with a This specification signed and witnessed this diaphragm of feit or equivalent material, of 13th day of November, 1883.'

au auxiliary diaphravm substantially as set T i form J EDWARD H. JOHNSON 5 5. In a. telephone, the cmbination of main VVituesses:

and auxiliary diaphragms, both of felt; or WM. H. MEADOWCROFT, equivalent material, substantially as seb forth. 1 H. XV. SEELY. 

